Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the ...Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.展开更多
The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hinde...The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.展开更多
Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplu...Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.展开更多
Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients par...Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc (Zn), boron (B) and manganese (Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that (i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro- and micro-nutrients in RWCS.(ii) The micronutrients (Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties (which differ under aerobic and anaerobic conditions) including soil pH, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration.展开更多
Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（O...Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（Oryza sativa L.） and wheat（Triticum aestivum L.） cropping systems in Lake Taihu region, China. The study was conducted on two types of paddy soils（Hydromorphic at Anzhen site, Wuxi City, and Degleyed at Xinzhuang site, Changshu City, Jiangsu Province） with different P status, and it covered 3 years with low, high and normal rainfall regimes. Four rates of mineral P fertilizer, i.e., no P（control）, 30 kg P ha^（–1） for rice and 20 kg P ha^（–1） for wheat（P_（30＋20））, 75 plus 40（P_（75＋40））, and 150 plus 80（P_（150＋80））, were applied as treatments. Runoff water from individual plots and runoff events was recorded and analyzed for total P and dissolved reactive P concentrations. Losses of total P and dissolved reactive P significantly increased with rainfall depth and P rates（P〈0.0001）. Annual total P losses ranged from 0.36–0.92 kg ha^–1 in control to 1.13–4.67 kg ha^–1 in P150＋80 at Anzhen, and correspondingly from 0.36–0.48 kg h^–1 to 1.26–1.88 kg ha^–1 at Xinzhuang, with 16–49% of total P as dissolved reactive P. In particular, large amounts of P were lost during heavy rainfall events that occurred shortly after P applications at Anzhen. On average of all P treatments, rice growing season constituted 37–86% of annual total P loss at Anzhen and 28–44% of that at Xinzhuang. In both crop seasons, P concentrations peaked in the first runoff events and decreased with time. During rice growing season, runoff P concentrations positively correlated（P〈0.0001） with P concentrations in field ponding water that was intentionally enclosed by construction of field bund. The relative high P loss during wheat growing season at Xinzhuang was due to high soil P status. In conclusion, P should be applied at rates balancing crop removal（20–30 kg P ha^–1 in this study） and at time excluding heavy rains. Moreover, irrigation and drainage water should be appropriately managed to reduce runoff P losses from rice-wheat cropping systems.展开更多
The common practice of establishing rice in the rice-wheat system in India is manual transplanting of seedlings in the puddled soil. Besides being costly, cumbersome, and time consuming, puddling results in degradatio...The common practice of establishing rice in the rice-wheat system in India is manual transplanting of seedlings in the puddled soil. Besides being costly, cumbersome, and time consuming, puddling results in degradation of soil and the formation of a hard pan, which impedes root growth of subsequent upland crops. In addition, decreased availability and increasing cost of labor have increased the cost of rice cultivation through conventional methods. Because of these concerns, there is a need for mechanized transplanting of rice which is less labor-intensive and can ensure optimum plant population under nonpuddled and/or no-till conditions. A large number of on-farm trials were conducted at farmers’ fields in Haryana, India, from 2006 to 2010 to evaluate the performance of the mechanical transplanted rice (MTR) under nonpuddled and no-till situations as compared to conventional puddled transplant rice (CPTR). Compared with CPTR, nonpuddled MTR produced 3%-11% higher grain yield in different years. Rice cultivars, viz. HKR47, HKR127, PR113, PR114, PB1, PB1121, CSR30, and Arize6129, performed consistently better under nonpuddled MTR as compared to CPTR. Performance of different cultivars (PR113, PR114, HKR47, and Pusa 44) was also better under no-till MTR as compared to CPTR. The “basmati” cultivar CSR30 performed equally in no-till MTR and CPTR systems. The results of our study suggest that rice can be easily grown under nonpuddled and no-till conditions with yield advantages over the CPTR system. Even in the case of similar yield between CPTR and MTR systems, the MTR system will help in reducing labor requirement and ultimately, will increase overall profits to farmers.展开更多
Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cott...Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cotton(Gossypium hirsutum L.)cropping system remains uncertain.The objective of this study was to quantify the long-term(10 years)impact of carbon(C)input on SOC sequestration,soil aggregation and crop yields in a wheat-cotton cropping system in the Yangtze River Valley,China.Five treatments were arranged with a single-factor randomized design as follows:no straw return(Control),return of wheat straw only(Wt),return of cotton straw only(Ct),return of 50%wheat and 50%cotton straw(Wh-Ch)and return of 100%wheat and 100%cotton straw(Wt-Ct).In comparison to the Control,the SOC content increased by 8.4 to 20.2%under straw return.A significant linear positive correlation between SOC sequestration and C input(1.42-7.19 Mg ha^(−1)yr^(−1))(P<0.05)was detected.The percentages of aggregates of sizes>2 and 1-2 mm at the 0-20 cm soil depth were also significantly elevated under straw return,with the greatest increase of the aggregate stability in the Wt-Ct treatment(28.1%).The average wheat yields increased by 12.4-36.0%and cotton yields increased by 29.4-73.7%,and significantly linear positive correlations were also detected between C input and the yields of wheat and cotton.The average sustainable yield index(SYI)reached a maximum value of 0.69 when the C input was 7.08 Mg ha^(−1)yr^(−1),which was close to the maximum value(SYI of 0.69,C input of 7.19 Mg ha^(−1)yr^(-1))in the Wt-Ct treatment.Overall,the return of both wheat and cotton straw was the best strategy for improving SOC sequestration,soil aggregation,yields and their sustainability in the wheat-cotton rotation system.展开更多
Winter wheat–summer maize cropping system in the North China Plain often experiences droughtinduced yield reduction in the wheat season and rainwater and nitrogen(N)fertilizer losses in the maize season.This study ai...Winter wheat–summer maize cropping system in the North China Plain often experiences droughtinduced yield reduction in the wheat season and rainwater and nitrogen(N)fertilizer losses in the maize season.This study aimed to identify an optimal interseasonal water-and N-management strategy to alleviate these losses.Four ratios of allocation of 360 kg N ha^(-1)between the wheat and maize seasons under one-time presowing root-zone irrigation(W0)and additional jointing and anthesis irrigation(W2)in wheat and one irrigation after maize sowing were set as follows:N1(120:240),N2(180:180),N3(240:120)and N4(300:60).The results showed that under W0,the N3 treatment produced the highest annual yield,crop water productivity(WPC),and nitrogen partial factor productivity(PFPN).Increased N allocation in wheat under W0 improved wheat yield without affecting maize yield,as surplus nitrate after wheat harvest was retained in the topsoil layers and available for the subsequent maize.Under W2,annual yield was largest in the N2 treatment.The risk of nitrate leaching increased in W2 when N application rate in wheat exceeded that of the N2 treatment,especially in the wet year.Compared to W2N2,the W0N3 maintained 95.2%grain yield over two years.The WPCwas higher in the W0 treatment than in the W2 treatment.Therefore,following limited total N rate,an appropriate fertilizer N transfer from maize to wheat season had the potential of a“triple win”for high annual yield,WPCand PFPN in a water-limited wheat–maize cropping system.展开更多
Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In thi...Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In this long-term field experiment(2008-2019),we researched bacterial and fungal diversity,composition,and community assemblage in the soil along a K fertilizer gradient in the wheat season(K0,no K fertilizer;K1,45 kg ha^(-1) K_(2)O;K_(2),90 kg ha^(-1)K_(2)O;K3,135 kg ha^(-1)K_(2)O)and in the maize season(K0,no K fertilizer;K_(1),150 kg ha^(-1) K_(2)O;K_(2),300 kg ha^(-1)K_(2)O;K_(3),450 kg ha^(-1)K_(2)O)using bacterial 16S rRNA and fungal internally transcribed spacer(ITS)data.We observed that environmental variables,such as mean annual soil temperature(MAT)and precipitation,available K,ammonium,nitrate,and organic matter,impacted the soil bacterial and fungal communities,and their impacts varied with fertilizer treatments and crop species.Furthermore,the relative abundance of bacteria involved in soil nutrient transformation(phylum Actinobacteria and class Alphaproteobacteria)in the wheat season was significantly increased compared to the maize season,and the optimal K fertilizer dosage(K2 treatment)boosted the relative bacterial abundance of soil nutrient transformation(genus Lactobacillus)and soil denitrification(phylum Proteobacteria)bacteria in the wheat season.The abundance of the soil bacterial community promoting root growth and nutrient absorption(genus Herbaspirillum)in the maize season was improved compared to the wheat season,and the K2 treatment enhanced the bacterial abundance of soil nutrient transformation(genus MND1)and soil nitrogen cycling(genus Nitrospira)genera in the maize season.The results indicated that the bacterial and fungal communities in the double-cropping system exhibited variable sensitivities and assembly mechanisms along a K fertilizer gradient,and microhabitats explained the largest amount of the variation in crop yields,and improved wheat?maize yields by 11.2-22.6 and 9.2-23.8%with K addition,respectively.These modes are shaped contemporaneously by the different meteorological factors and soil nutrient changes in the K fertilizer gradients.展开更多
Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their...Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha<sup>-1</sup>) and contributed the most total N (167 kg∙ha<sup>-1</sup>) and total C (3043 kg∙ha<sup>-1</sup>) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha<sup>-1</sup> with a total N yield of 319 kg N ha<sup>-1</sup> and total C production of 3835 kg C ha<sup>-1</sup>. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.展开更多
Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for ...Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for the vegetative stage of the green gram (Vigna. radiata L.) over 5 years (2020, 2018, 2017, 2015, and 2013) for agroecological zone IV and V in Kenya. The years chosen were those whose satellite resolution data was available for the vegetative stage of crop growth in the short rain season (October, November, December (OND)). We used Landsat 8 OLI satellite imagery in this study. Cropping pattern data for the study area were evaluated by calculating the Top of Atmosphere reflectance. Farms geo-referencing, along with field data collection, was undertaken to extract Top of Atmosphere reflectance for bands 2, 3, 4 and 7. We also carried a spectral similarity assessment on the various cropping patterns. The spectral reflectance ranged from 0.07696 - 0.09632, 0.07466 - 0.09467, 0.0704047 - 0.12188,0.19822 - 0.24387, 0.19269 - 0.26900, and 0.11354 - 0.20815 for bands 2, 3, 4, 5, 6, and 7 for green gram, respectively. The results showed a dissimilarity among the various cropping patterns. The lowest dissimilarity index was 0.027 for the maize (Zea mays L.) bean (Phaseolus vulgaris) versus the maize-pigeon pea (Cajanus cajan) crop, while the highest dissimilarity index was 0.443 for the maize bean versus the maize bean and cowpea cropping patterns. High crop dissimilarities experienced across the cropping pattern through these spectral reflectance values confirm that the green gram was potentially identifiable. The results can be used in crop type identification in agroecological lower midland zone IV and V for mung bean management. This study therefore suggests that use of reflectance data in remote sensing of agricultural ecosystems would aid in planning, management, and crop allocation to different ecozones.展开更多
In recent years,the area dedicated to cotton cultivation in eastern Henan Province has experienced a continuous decline.Developing efficient multi-cropping systems for cotton and increasing the multiple cropping index...In recent years,the area dedicated to cotton cultivation in eastern Henan Province has experienced a continuous decline.Developing efficient multi-cropping systems for cotton and increasing the multiple cropping index represent effective strategies to stabilize the cotton planting area and enhance the income of cotton farmers.This paper presents an overview of intercropping systems and the benefits associated with cotton rotation and intercropping practices.Specifically,it discusses the"early maturing cotton-wheat"rotation system,the"cotton-watermelon"intercropping system,the"cotton-Dutch bean"intercropping system,and the"early maturing cotton-peanut-garlic"intercropping system.展开更多
Continuous cropping can bring economic benefits in a short time and meet the growing demand of agricultural products such as grain,but long-term continuous cropping will accelerate soil degradation,lead to the reducti...Continuous cropping can bring economic benefits in a short time and meet the growing demand of agricultural products such as grain,but long-term continuous cropping will accelerate soil degradation,lead to the reduction of crop yield and the increase of disease rate,and destroy the balance of soil microbial structure.Therefore,it is not conducive to the sustainable development of soil ecosystem.In this paper,the problems caused by continuous cropping,such as imbalance of soil microbial flora,decrease of biodiversity,accumulation of root exudates and their effects on soil fertility and crop growth,were summarized,and some measures were suggested to alleviate the obstacles of continuous cropping,such as reasonable rotation,adjustment of intercropping planting mode and application of biological fertilizers.Moreover,the paper also looked forward to the development trend of continuous cropping obstacle reduction techniques,including the integration and application of biological techniques,the promotion of green ecological techniques and the application of intelligent management system.This study provides theoretical basis and technical support for the research of continuous cropping obstacle reduction techniques and promote the healthy and sustainable development of modern agriculture.展开更多
Continuous cropping has become a common form of agricultural production at present, but with the increase of continuous cropping years, continuous cropping obstacles such as soil-borne diseases and plant growth potent...Continuous cropping has become a common form of agricultural production at present, but with the increase of continuous cropping years, continuous cropping obstacles such as soil-borne diseases and plant growth potential decline are becoming more and more common. At present, the causes of continuous cropping obstacles and continuous cropping restoration have become a hot issue in agricultural research. This paper summarized the effects of continuous cropping obstacles on soil microbial community structure and main technical methods to repair continuous cropping obstacles, such as agricultural measure management, microbial balance adjustment and soil improvement, aiming to provide theoretical reference for protecting the sustainable utilization of soil ecosystem and ensuring the stability of crop production.展开更多
At present,long-term continuous cropping in agricultural production has formed a relatively common development trend.With the increase of continuous cropping years,soil phenolic acids are also affected to varying degr...At present,long-term continuous cropping in agricultural production has formed a relatively common development trend.With the increase of continuous cropping years,soil phenolic acids are also affected to varying degrees.This paper summarized the effects of continuous cropping on soil phenolic acids and the research progress of continuous cropping obstacle reduction techniques,aiming at providing theoretical basis and technical support for the research of continuous cropping obstacle reduction techniques and promoting the healthy and sustainable development of modern agriculture.展开更多
Ammonia (NH_3) emissions should be mitigated to improve environmental quality.Croplands are one of the largest NH_3sources,they must be managed properly to reduce their emissions while achieving the target yields.Here...Ammonia (NH_3) emissions should be mitigated to improve environmental quality.Croplands are one of the largest NH_3sources,they must be managed properly to reduce their emissions while achieving the target yields.Herein,we report the NH_3 emissions,crop yield and changes in soil fertility in a long-term trial with various fertilization regimes,to explore whether NH_3 emissions can be significantly reduced using the 4R nutrient stewardship (4Rs),and its interaction with the organic amendments (i.e.,manure and straw) in a wheat–maize rotation.Implementing the 4Rs significantly reduced NH_3 emissions to 6 kg N ha~(–1) yr~(–1) and the emission factor to 1.72%,without compromising grain yield (12.37 Mg ha~(–1) yr~(–1))and soil fertility (soil organic carbon of 7.58 g kg~(–1)) compared to the conventional chemical N management.When using the 4R plus manure,NH_3 emissions (7 kg N ha~(–1) yr~(–1)) and the emission factor (1.74%) were as low as 4Rs,and grain yield and soil organic carbon increased to 14.79 Mg ha~(–1) yr~(–1) and 10.09 g kg~(–1),respectively.Partial manure substitution not only significantly reduced NH_3 emissions but also increased crop yields and improved soil fertility,compared to conventional chemical N management.Straw return exerted a minor effect on NH_3 emissions.These results highlight that 4R plus manure,which couples nitrogen and carbon management can help achieve both high yields and low environmental costs.展开更多
Relay cropping of Poaceae and Fabaceae promotes high yield and land-use efficiency by allowing a double harvest.However,it is difficult to increase yield synergistically because of the reduced photosynthetic abilities...Relay cropping of Poaceae and Fabaceae promotes high yield and land-use efficiency by allowing a double harvest.However,it is difficult to increase yield synergistically because of the reduced photosynthetic abilities of legume leaves under the shade of graminoids.Leaf photosynthetic capacity in relay cropping systems is associated with ecological niche differentiation and photosynthetic compensation after restoration of normal light.We conducted a field experiment in southwest China in 2020–2021 to evaluate the effects of three cropping patterns:maize–soybean relay cropping(IMS),monoculture maize(MM),and monoculture soybean(SS),and N application levels:no N application(NN:0 kg N ha^(−1)),reduced N(RN:180 kg N ha^(−1)),and conventional N(CN:240 kg N ha^(−1)).Compared to monocropping,relay cropping increased the stay-green traits of maize and soybean by 13%and 89%,respectively.Relay cropping prolonged the leaf stay-green duration in the maize and soybean lag phase by almost 4 and 8 days,respectively.Relay cropping maize(IM)increased the leaf area index(LAI)by 79.4%to 88.5%under NN and 55.5%to 148%under RN.Relay cropping soybean(IS)increased the LAI from 115%to 437%at days 40 to 50 after anthesis.IM increased yield by 65.6%.IS increased yield by 9.7%.HI and system yield were at their highest values under RN.In the relay cropping system,reduced N application extended green leaf duration,increased photosynthesis inside the canopy at multiple levels,ultimately increases soybean yield synergistically.展开更多
Continuous cropping(CC)obstacle is a major threat in legume crops production;however,the underlying mechanisms concerning the roles allelochemicals play in CC obstacle are poorly understood.The current 2-year study wa...Continuous cropping(CC)obstacle is a major threat in legume crops production;however,the underlying mechanisms concerning the roles allelochemicals play in CC obstacle are poorly understood.The current 2-year study was conducted to investigate the effects of different kinds and concentrations of allelochemicals,p-hydroxybenzoic acid(H),cinnamic acid(C),phthalic acid(P),and their mixtures(M)on peanut root growth and productivity in response to CC obstacle.Treatment with H,C,P,and M significantly decreased the plant height,dry weight of the leaves and stems,number of branches,and length of the lateral stem compared with control.Exogenous application of H,C,P,and M inhibited the peanut root growth as indicated by the decreased root morphological characters.The allelochemicals also induced the cell membrane oxidation even though the antioxidant enzymes activities were significantly increased in peanut roots.Meanwhile,treatment with H,C,P,and M reduced the contents of total soluble sugar and total soluble protein.Analysis of ATPase activity,nitrate reductase activity,and root system activity revealed that the inhibition effects of allelochemicals on peanut roots might be due to the decrease in activities of ATPase and NR,and the inhibition of root system.Consequently,allelochemicals significantly decreased the pod yield of peanut compared with control.Our results demonstrate that allelochemicals play a dominant role in CC obstacle-induced peanut growth inhibition and yield reduction through damaging the root antioxidant system,unbalancing the osmolytes accumulation,and decreasing the activities of root-related enzymes.展开更多
The lower availability of N is one of the most important limiting factors impeding crop yield enhancement among the various factors that affect crop yield under the multiple-cropping agroecosystem in China.In this stu...The lower availability of N is one of the most important limiting factors impeding crop yield enhancement among the various factors that affect crop yield under the multiple-cropping agroecosystem in China.In this study,the recovery of a single application of 15N-labeled fertilizer or residues in rice-wheat cropping system was determined,in order to provide theoretical foundation for the nitrogen management in sustainable agricultural production.A continuous trace experiment was conducted for 15N microplots by using randomized block design with four treatments and four replications（T1 = 15N-labeled fertilizer with crop residue incorporation,T2 = 15N-labeled residues,T3 = 14N fertilizer to generate unlabeled crop residue,and T4 = 15Nlabeled fertilizer without crop residue incorporation）.Our results showed that,on average,17.17 and 12.01% of crop N was derived from N fertilizer and 15N-labeled residues,respectively during the first growing season,suggesting that approximately 82.83 or 87.99% of crop N was derived directly from soil N pool.There was a larger difference in the 15N recovery pattern in crop when N was applied as fertilizer or residues,i.e.,most of crop N derived from N fertilizer was absorbed in the first growing season（92.04%）,and the relevant value was 38.03% when 15N-labeled residues were applied.This implied that most of N fertilizer was recovered in the present cropping season,while a longer residue effect will be found for 15N-labeled residues.Thus,the average recovery of N fertilizer and N residue in the soil after the first growing season was 33.46 and 85.64%,respectively.The recovery of applied N in soil when N was applied as residues was significantly higher than that when N was applied as fertilizer.There was a larger difference in the total 15N recovery in plant and soil when N was applied as fertilizer or residues.By the end of the fifth or sixth cropping season,the total 15N recovery in plant and soil when N was applied as fertilizer or residues were estimated at 64.38 and 79.11%,respectively.On the contrary,there was little difference between the practices of residue incorporation and residue removal following the N fertilizer application.N fertilizer appeared to be more readily available to crops than residue-N,and residue-N replenished soil N pool,especially N in soil organic matter,much more than N fertilizer after six growing seasons.Therefore,residue-N is a better source for sustaining N content of soil organic matter.Thus,one possible management practice is to use both organic and inorganic N sources simultaneously to improve the use efficiency of N while protecting the sustainability of soil.展开更多
文摘Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.
基金funded by the National Key Technologies Research and Development Program of China(2006BAD02A05)the Science and Technology Project for Public (Agriculture)the Ministry of Agriculture, China (200903050-4)
文摘The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.
基金Funding was provided by the National Key Research and Development Program of China(2017YFD0301203,2017YFD0300100,and 2018YFD0300803)Jiangsu Agriculture Science and Technology Innovation Fund(CX(18)1002).
文摘Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.
文摘Rice-wheat cropping system (RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc (Zn), boron (B) and manganese (Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that (i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro- and micro-nutrients in RWCS.(ii) The micronutrients (Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties (which differ under aerobic and anaerobic conditions) including soil pH, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration.
基金funded by the Special Fund for AgroScientific Research in the Public Interest, China (201003014)
文摘Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（Oryza sativa L.） and wheat（Triticum aestivum L.） cropping systems in Lake Taihu region, China. The study was conducted on two types of paddy soils（Hydromorphic at Anzhen site, Wuxi City, and Degleyed at Xinzhuang site, Changshu City, Jiangsu Province） with different P status, and it covered 3 years with low, high and normal rainfall regimes. Four rates of mineral P fertilizer, i.e., no P（control）, 30 kg P ha^（–1） for rice and 20 kg P ha^（–1） for wheat（P_（30＋20））, 75 plus 40（P_（75＋40））, and 150 plus 80（P_（150＋80））, were applied as treatments. Runoff water from individual plots and runoff events was recorded and analyzed for total P and dissolved reactive P concentrations. Losses of total P and dissolved reactive P significantly increased with rainfall depth and P rates（P〈0.0001）. Annual total P losses ranged from 0.36–0.92 kg ha^–1 in control to 1.13–4.67 kg ha^–1 in P150＋80 at Anzhen, and correspondingly from 0.36–0.48 kg h^–1 to 1.26–1.88 kg ha^–1 at Xinzhuang, with 16–49% of total P as dissolved reactive P. In particular, large amounts of P were lost during heavy rainfall events that occurred shortly after P applications at Anzhen. On average of all P treatments, rice growing season constituted 37–86% of annual total P loss at Anzhen and 28–44% of that at Xinzhuang. In both crop seasons, P concentrations peaked in the first runoff events and decreased with time. During rice growing season, runoff P concentrations positively correlated（P〈0.0001） with P concentrations in field ponding water that was intentionally enclosed by construction of field bund. The relative high P loss during wheat growing season at Xinzhuang was due to high soil P status. In conclusion, P should be applied at rates balancing crop removal（20–30 kg P ha^–1 in this study） and at time excluding heavy rains. Moreover, irrigation and drainage water should be appropriately managed to reduce runoff P losses from rice-wheat cropping systems.
文摘The common practice of establishing rice in the rice-wheat system in India is manual transplanting of seedlings in the puddled soil. Besides being costly, cumbersome, and time consuming, puddling results in degradation of soil and the formation of a hard pan, which impedes root growth of subsequent upland crops. In addition, decreased availability and increasing cost of labor have increased the cost of rice cultivation through conventional methods. Because of these concerns, there is a need for mechanized transplanting of rice which is less labor-intensive and can ensure optimum plant population under nonpuddled and/or no-till conditions. A large number of on-farm trials were conducted at farmers’ fields in Haryana, India, from 2006 to 2010 to evaluate the performance of the mechanical transplanted rice (MTR) under nonpuddled and no-till situations as compared to conventional puddled transplant rice (CPTR). Compared with CPTR, nonpuddled MTR produced 3%-11% higher grain yield in different years. Rice cultivars, viz. HKR47, HKR127, PR113, PR114, PB1, PB1121, CSR30, and Arize6129, performed consistently better under nonpuddled MTR as compared to CPTR. Performance of different cultivars (PR113, PR114, HKR47, and Pusa 44) was also better under no-till MTR as compared to CPTR. The “basmati” cultivar CSR30 performed equally in no-till MTR and CPTR systems. The results of our study suggest that rice can be easily grown under nonpuddled and no-till conditions with yield advantages over the CPTR system. Even in the case of similar yield between CPTR and MTR systems, the MTR system will help in reducing labor requirement and ultimately, will increase overall profits to farmers.
基金supported by the National Natural Science Foundation of China(32071968)the Jiangsu Agricultural Science and Technology Innovation Fund,China(CX(22)2015))the Jiangsu Collaborative Innovation Center for Modern Crop Production,China。
文摘Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cotton(Gossypium hirsutum L.)cropping system remains uncertain.The objective of this study was to quantify the long-term(10 years)impact of carbon(C)input on SOC sequestration,soil aggregation and crop yields in a wheat-cotton cropping system in the Yangtze River Valley,China.Five treatments were arranged with a single-factor randomized design as follows:no straw return(Control),return of wheat straw only(Wt),return of cotton straw only(Ct),return of 50%wheat and 50%cotton straw(Wh-Ch)and return of 100%wheat and 100%cotton straw(Wt-Ct).In comparison to the Control,the SOC content increased by 8.4 to 20.2%under straw return.A significant linear positive correlation between SOC sequestration and C input(1.42-7.19 Mg ha^(−1)yr^(−1))(P<0.05)was detected.The percentages of aggregates of sizes>2 and 1-2 mm at the 0-20 cm soil depth were also significantly elevated under straw return,with the greatest increase of the aggregate stability in the Wt-Ct treatment(28.1%).The average wheat yields increased by 12.4-36.0%and cotton yields increased by 29.4-73.7%,and significantly linear positive correlations were also detected between C input and the yields of wheat and cotton.The average sustainable yield index(SYI)reached a maximum value of 0.69 when the C input was 7.08 Mg ha^(−1)yr^(−1),which was close to the maximum value(SYI of 0.69,C input of 7.19 Mg ha^(−1)yr^(-1))in the Wt-Ct treatment.Overall,the return of both wheat and cotton straw was the best strategy for improving SOC sequestration,soil aggregation,yields and their sustainability in the wheat-cotton rotation system.
基金supported by Hebei Province Key Research Project(21327003D-1)Beijing Science and Technology Planning Project(Z221100006422005)+1 种基金China Postdoctoral Science Foundation(2023M743815)China Agriculture Research System(CARS301)。
文摘Winter wheat–summer maize cropping system in the North China Plain often experiences droughtinduced yield reduction in the wheat season and rainwater and nitrogen(N)fertilizer losses in the maize season.This study aimed to identify an optimal interseasonal water-and N-management strategy to alleviate these losses.Four ratios of allocation of 360 kg N ha^(-1)between the wheat and maize seasons under one-time presowing root-zone irrigation(W0)and additional jointing and anthesis irrigation(W2)in wheat and one irrigation after maize sowing were set as follows:N1(120:240),N2(180:180),N3(240:120)and N4(300:60).The results showed that under W0,the N3 treatment produced the highest annual yield,crop water productivity(WPC),and nitrogen partial factor productivity(PFPN).Increased N allocation in wheat under W0 improved wheat yield without affecting maize yield,as surplus nitrate after wheat harvest was retained in the topsoil layers and available for the subsequent maize.Under W2,annual yield was largest in the N2 treatment.The risk of nitrate leaching increased in W2 when N application rate in wheat exceeded that of the N2 treatment,especially in the wet year.Compared to W2N2,the W0N3 maintained 95.2%grain yield over two years.The WPCwas higher in the W0 treatment than in the W2 treatment.Therefore,following limited total N rate,an appropriate fertilizer N transfer from maize to wheat season had the potential of a“triple win”for high annual yield,WPCand PFPN in a water-limited wheat–maize cropping system.
基金funded by the National Key Research and Development Program of China(2023YFD150050504)the Key Research and Development Program of Shandong Province,China(2022SFGC0301)the Strategic Priority Research Program of the Chinese Academy of Sciences-Development and Application Technology of Special Package Fertilizer for Improving Albic Soil(XDA28100203)。
文摘Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In this long-term field experiment(2008-2019),we researched bacterial and fungal diversity,composition,and community assemblage in the soil along a K fertilizer gradient in the wheat season(K0,no K fertilizer;K1,45 kg ha^(-1) K_(2)O;K_(2),90 kg ha^(-1)K_(2)O;K3,135 kg ha^(-1)K_(2)O)and in the maize season(K0,no K fertilizer;K_(1),150 kg ha^(-1) K_(2)O;K_(2),300 kg ha^(-1)K_(2)O;K_(3),450 kg ha^(-1)K_(2)O)using bacterial 16S rRNA and fungal internally transcribed spacer(ITS)data.We observed that environmental variables,such as mean annual soil temperature(MAT)and precipitation,available K,ammonium,nitrate,and organic matter,impacted the soil bacterial and fungal communities,and their impacts varied with fertilizer treatments and crop species.Furthermore,the relative abundance of bacteria involved in soil nutrient transformation(phylum Actinobacteria and class Alphaproteobacteria)in the wheat season was significantly increased compared to the maize season,and the optimal K fertilizer dosage(K2 treatment)boosted the relative bacterial abundance of soil nutrient transformation(genus Lactobacillus)and soil denitrification(phylum Proteobacteria)bacteria in the wheat season.The abundance of the soil bacterial community promoting root growth and nutrient absorption(genus Herbaspirillum)in the maize season was improved compared to the wheat season,and the K2 treatment enhanced the bacterial abundance of soil nutrient transformation(genus MND1)and soil nitrogen cycling(genus Nitrospira)genera in the maize season.The results indicated that the bacterial and fungal communities in the double-cropping system exhibited variable sensitivities and assembly mechanisms along a K fertilizer gradient,and microhabitats explained the largest amount of the variation in crop yields,and improved wheat?maize yields by 11.2-22.6 and 9.2-23.8%with K addition,respectively.These modes are shaped contemporaneously by the different meteorological factors and soil nutrient changes in the K fertilizer gradients.
文摘Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha<sup>-1</sup>) and contributed the most total N (167 kg∙ha<sup>-1</sup>) and total C (3043 kg∙ha<sup>-1</sup>) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha<sup>-1</sup> with a total N yield of 319 kg N ha<sup>-1</sup> and total C production of 3835 kg C ha<sup>-1</sup>. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.
文摘Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for the vegetative stage of the green gram (Vigna. radiata L.) over 5 years (2020, 2018, 2017, 2015, and 2013) for agroecological zone IV and V in Kenya. The years chosen were those whose satellite resolution data was available for the vegetative stage of crop growth in the short rain season (October, November, December (OND)). We used Landsat 8 OLI satellite imagery in this study. Cropping pattern data for the study area were evaluated by calculating the Top of Atmosphere reflectance. Farms geo-referencing, along with field data collection, was undertaken to extract Top of Atmosphere reflectance for bands 2, 3, 4 and 7. We also carried a spectral similarity assessment on the various cropping patterns. The spectral reflectance ranged from 0.07696 - 0.09632, 0.07466 - 0.09467, 0.0704047 - 0.12188,0.19822 - 0.24387, 0.19269 - 0.26900, and 0.11354 - 0.20815 for bands 2, 3, 4, 5, 6, and 7 for green gram, respectively. The results showed a dissimilarity among the various cropping patterns. The lowest dissimilarity index was 0.027 for the maize (Zea mays L.) bean (Phaseolus vulgaris) versus the maize-pigeon pea (Cajanus cajan) crop, while the highest dissimilarity index was 0.443 for the maize bean versus the maize bean and cowpea cropping patterns. High crop dissimilarities experienced across the cropping pattern through these spectral reflectance values confirm that the green gram was potentially identifiable. The results can be used in crop type identification in agroecological lower midland zone IV and V for mung bean management. This study therefore suggests that use of reflectance data in remote sensing of agricultural ecosystems would aid in planning, management, and crop allocation to different ecozones.
基金Supported by China Agricultural Industry Research System(CARS-15-38).
文摘In recent years,the area dedicated to cotton cultivation in eastern Henan Province has experienced a continuous decline.Developing efficient multi-cropping systems for cotton and increasing the multiple cropping index represent effective strategies to stabilize the cotton planting area and enhance the income of cotton farmers.This paper presents an overview of intercropping systems and the benefits associated with cotton rotation and intercropping practices.Specifically,it discusses the"early maturing cotton-wheat"rotation system,the"cotton-watermelon"intercropping system,the"cotton-Dutch bean"intercropping system,and the"early maturing cotton-peanut-garlic"intercropping system.
基金Supported by Key Project of Yunnan Provincial Science and Technology Plan(202202AE090015)Scientific Research Fund of Yunnan Education Department(2024Y742+3 种基金2023Y0863)National Natural Science Foundation of China(42067009)2023 Undergraduate Innovation and Entrepreneurship Training Program of Yunnan Education Department(S202311393044S202311393061).
文摘Continuous cropping can bring economic benefits in a short time and meet the growing demand of agricultural products such as grain,but long-term continuous cropping will accelerate soil degradation,lead to the reduction of crop yield and the increase of disease rate,and destroy the balance of soil microbial structure.Therefore,it is not conducive to the sustainable development of soil ecosystem.In this paper,the problems caused by continuous cropping,such as imbalance of soil microbial flora,decrease of biodiversity,accumulation of root exudates and their effects on soil fertility and crop growth,were summarized,and some measures were suggested to alleviate the obstacles of continuous cropping,such as reasonable rotation,adjustment of intercropping planting mode and application of biological fertilizers.Moreover,the paper also looked forward to the development trend of continuous cropping obstacle reduction techniques,including the integration and application of biological techniques,the promotion of green ecological techniques and the application of intelligent management system.This study provides theoretical basis and technical support for the research of continuous cropping obstacle reduction techniques and promote the healthy and sustainable development of modern agriculture.
基金Supported by National Natural Science Foundation of China(42067009)Scientific Research Project of Yunnan Provincial Department of Education(2024Y742,2023Y0863)+2 种基金Project of Kunming Municipal Commission of Development and Reform(Kunming Spring City Industrial Technology Leading Talents)Science and Technology Major Project of Yunnan Province Science and Technology Department(202202AE090015-02)Yunnan Students’innovation and entrepreneurship training program(S202311393044,S202311393061)。
文摘Continuous cropping has become a common form of agricultural production at present, but with the increase of continuous cropping years, continuous cropping obstacles such as soil-borne diseases and plant growth potential decline are becoming more and more common. At present, the causes of continuous cropping obstacles and continuous cropping restoration have become a hot issue in agricultural research. This paper summarized the effects of continuous cropping obstacles on soil microbial community structure and main technical methods to repair continuous cropping obstacles, such as agricultural measure management, microbial balance adjustment and soil improvement, aiming to provide theoretical reference for protecting the sustainable utilization of soil ecosystem and ensuring the stability of crop production.
基金Supported by Scientific Research Fund of Yunnan Education Department(2024Y742,2023Y0863)National Natural Science Foundation of China(42067009)+1 种基金College Students'Innovative Training Plan Program of Yunnan Education Department in 2023(S202311393044,S202311393061)Key Project of Science and Technology Program of Yunnan Province(202202AE090015).
文摘At present,long-term continuous cropping in agricultural production has formed a relatively common development trend.With the increase of continuous cropping years,soil phenolic acids are also affected to varying degrees.This paper summarized the effects of continuous cropping on soil phenolic acids and the research progress of continuous cropping obstacle reduction techniques,aiming at providing theoretical basis and technical support for the research of continuous cropping obstacle reduction techniques and promoting the healthy and sustainable development of modern agriculture.
基金supported by the Hainan Key Research and Development Project, China (ZDYF2021XDNY184)the Hainan Provincial Natural Science Foundation of China (422RC597)+2 种基金the National Natural Science Foundation of China (41830751)the Hainan Major Science and Technology Program, China (ZDKJ2021008)the Hainan University Startup Fund,China (KYQD(ZR)-20098)。
文摘Ammonia (NH_3) emissions should be mitigated to improve environmental quality.Croplands are one of the largest NH_3sources,they must be managed properly to reduce their emissions while achieving the target yields.Herein,we report the NH_3 emissions,crop yield and changes in soil fertility in a long-term trial with various fertilization regimes,to explore whether NH_3 emissions can be significantly reduced using the 4R nutrient stewardship (4Rs),and its interaction with the organic amendments (i.e.,manure and straw) in a wheat–maize rotation.Implementing the 4Rs significantly reduced NH_3 emissions to 6 kg N ha~(–1) yr~(–1) and the emission factor to 1.72%,without compromising grain yield (12.37 Mg ha~(–1) yr~(–1))and soil fertility (soil organic carbon of 7.58 g kg~(–1)) compared to the conventional chemical N management.When using the 4R plus manure,NH_3 emissions (7 kg N ha~(–1) yr~(–1)) and the emission factor (1.74%) were as low as 4Rs,and grain yield and soil organic carbon increased to 14.79 Mg ha~(–1) yr~(–1) and 10.09 g kg~(–1),respectively.Partial manure substitution not only significantly reduced NH_3 emissions but also increased crop yields and improved soil fertility,compared to conventional chemical N management.Straw return exerted a minor effect on NH_3 emissions.These results highlight that 4R plus manure,which couples nitrogen and carbon management can help achieve both high yields and low environmental costs.
基金the Special Fund for the Industrial Technology System Construction of Modem Agriculture(CARS-04-PS20)the National Natural Science Foundation of China(31872856,31671625)the National Key Research and Development Program of China(2021YFF1000500)。
文摘Relay cropping of Poaceae and Fabaceae promotes high yield and land-use efficiency by allowing a double harvest.However,it is difficult to increase yield synergistically because of the reduced photosynthetic abilities of legume leaves under the shade of graminoids.Leaf photosynthetic capacity in relay cropping systems is associated with ecological niche differentiation and photosynthetic compensation after restoration of normal light.We conducted a field experiment in southwest China in 2020–2021 to evaluate the effects of three cropping patterns:maize–soybean relay cropping(IMS),monoculture maize(MM),and monoculture soybean(SS),and N application levels:no N application(NN:0 kg N ha^(−1)),reduced N(RN:180 kg N ha^(−1)),and conventional N(CN:240 kg N ha^(−1)).Compared to monocropping,relay cropping increased the stay-green traits of maize and soybean by 13%and 89%,respectively.Relay cropping prolonged the leaf stay-green duration in the maize and soybean lag phase by almost 4 and 8 days,respectively.Relay cropping maize(IM)increased the leaf area index(LAI)by 79.4%to 88.5%under NN and 55.5%to 148%under RN.Relay cropping soybean(IS)increased the LAI from 115%to 437%at days 40 to 50 after anthesis.IM increased yield by 65.6%.IS increased yield by 9.7%.HI and system yield were at their highest values under RN.In the relay cropping system,reduced N application extended green leaf duration,increased photosynthesis inside the canopy at multiple levels,ultimately increases soybean yield synergistically.
基金supported by the National Key R&D Program of China(2018YFD1000902)the Natural Science Foundation of Shandong Province(ZR2021QC163).
文摘Continuous cropping(CC)obstacle is a major threat in legume crops production;however,the underlying mechanisms concerning the roles allelochemicals play in CC obstacle are poorly understood.The current 2-year study was conducted to investigate the effects of different kinds and concentrations of allelochemicals,p-hydroxybenzoic acid(H),cinnamic acid(C),phthalic acid(P),and their mixtures(M)on peanut root growth and productivity in response to CC obstacle.Treatment with H,C,P,and M significantly decreased the plant height,dry weight of the leaves and stems,number of branches,and length of the lateral stem compared with control.Exogenous application of H,C,P,and M inhibited the peanut root growth as indicated by the decreased root morphological characters.The allelochemicals also induced the cell membrane oxidation even though the antioxidant enzymes activities were significantly increased in peanut roots.Meanwhile,treatment with H,C,P,and M reduced the contents of total soluble sugar and total soluble protein.Analysis of ATPase activity,nitrate reductase activity,and root system activity revealed that the inhibition effects of allelochemicals on peanut roots might be due to the decrease in activities of ATPase and NR,and the inhibition of root system.Consequently,allelochemicals significantly decreased the pod yield of peanut compared with control.Our results demonstrate that allelochemicals play a dominant role in CC obstacle-induced peanut growth inhibition and yield reduction through damaging the root antioxidant system,unbalancing the osmolytes accumulation,and decreasing the activities of root-related enzymes.
文摘The lower availability of N is one of the most important limiting factors impeding crop yield enhancement among the various factors that affect crop yield under the multiple-cropping agroecosystem in China.In this study,the recovery of a single application of 15N-labeled fertilizer or residues in rice-wheat cropping system was determined,in order to provide theoretical foundation for the nitrogen management in sustainable agricultural production.A continuous trace experiment was conducted for 15N microplots by using randomized block design with four treatments and four replications（T1 = 15N-labeled fertilizer with crop residue incorporation,T2 = 15N-labeled residues,T3 = 14N fertilizer to generate unlabeled crop residue,and T4 = 15Nlabeled fertilizer without crop residue incorporation）.Our results showed that,on average,17.17 and 12.01% of crop N was derived from N fertilizer and 15N-labeled residues,respectively during the first growing season,suggesting that approximately 82.83 or 87.99% of crop N was derived directly from soil N pool.There was a larger difference in the 15N recovery pattern in crop when N was applied as fertilizer or residues,i.e.,most of crop N derived from N fertilizer was absorbed in the first growing season（92.04%）,and the relevant value was 38.03% when 15N-labeled residues were applied.This implied that most of N fertilizer was recovered in the present cropping season,while a longer residue effect will be found for 15N-labeled residues.Thus,the average recovery of N fertilizer and N residue in the soil after the first growing season was 33.46 and 85.64%,respectively.The recovery of applied N in soil when N was applied as residues was significantly higher than that when N was applied as fertilizer.There was a larger difference in the total 15N recovery in plant and soil when N was applied as fertilizer or residues.By the end of the fifth or sixth cropping season,the total 15N recovery in plant and soil when N was applied as fertilizer or residues were estimated at 64.38 and 79.11%,respectively.On the contrary,there was little difference between the practices of residue incorporation and residue removal following the N fertilizer application.N fertilizer appeared to be more readily available to crops than residue-N,and residue-N replenished soil N pool,especially N in soil organic matter,much more than N fertilizer after six growing seasons.Therefore,residue-N is a better source for sustaining N content of soil organic matter.Thus,one possible management practice is to use both organic and inorganic N sources simultaneously to improve the use efficiency of N while protecting the sustainability of soil.
